Considering the COVID-19 pandemic that has affected the whole world and many aspects of our lives, this research aimed to examine the impact of the COVID-19 pandemic on the chnage of eating habits and behavior of the adult population in the Republic of Croatia. An additional aim was to determine whether there was a change in the body weight of the respondents compared to the period before the pandemic and if there were differences considering to gender, age, educational and employment status. The research was conducted with an online survey questionnare in the period from April to June 2021. A total of 297 respondents participated, most of whom were female (75%). Most of them are in the age group of 20 to 29 years. Among the respondents, there is a high percentage of smokers (32%), ae well as those who consume alcohol (68%). The results of this study show that one third of the subjects gained weight (34.6%), the majority maintained the same weight (48.8%), and the rest reduced their body weight. The fact that as many as a third of the respondents gained weight during the pandemic is a worrying, but in line with the results of similar research. However, on the other hand, the obtained results are surprising considering that the majority of respondents stated that at the time of the pandemic they increased their vegetable intake compared to the time before the pandemic, without a significant change in the consumption of other food groups. No correlation was found between body weight change with regard to gender, age, employment, education, and consumption of alcohol and tobacco products. Furthermore, physical activity did not affect the change in body weight as the majority of respondents stated that the level of their physical activity did not change compared to the time before the pandemic. Most respondents stated that they were exposed to the higher level of stress which did not affect the length and quality of sleep. More frequent consumption of fast food was reported by the employed compared to the unemployed participants. Data that is not in line with the expetations is that women consume more meat than men. This research confirms as well the need to raise the awareness about the negative consequences of the COVID-19 pandemic on health and the importance of a proper diet and regular physical activity during this challenging times.